Subtask 1 (7 points): $n \le 5000$
Subtask 2 (12 points): $n \le 3 \cdot 10^5,$ $y_i=0$ for all circles.
Subtask 3 (15 points): $n \le 3 \cdot 10^5$, every circle intersects with at most 1 other circle.
Subtask 4 (23 points): $n \le 3 \cdot 10^5$, all circles have the same radius.
Subtask 5 (30 points): $n \le 10^5$
Subtask 6 (13 points): $n \le 3 \cdot 10^5$